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Tim H.
Tim H., HVAC Professional
Category: HVAC
Satisfied Customers: 3971
Experience:  Experienced in all aspects of HVAC, both residential and commercial.
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Problem started, someone stole the disconnect from my

Customer Question

Problem started, someone stole the disconnect from my outdoor A/C. I replaced the fuses and holder/plug in. My thermostat was dead, it says HOLD AC so I changed batteries. No go. The switch next to furnace has 120v going to it no matter if it's on or off. Control Board gets 120v, and 120v leave the board, to the Primary side of Transformer, and just 'trace' voltage on other side, but the other day it read 49v. I replaced the control board, but no power to turn furnace on. Thermostat red wire has 24v. My furnace is Goodman GMPN120-5, My Thermostat is a Chronotherm III.
Submitted: 1 month ago.
Category: HVAC
Customer: replied 1 month ago.
The Thermostat is getting 15-16v red wire.
Expert:  Tim H. replied 1 month ago.

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Thanks for the opportunity to help!

Expert:  Tim H. replied 1 month ago.

Did you still need assistance with this?

Customer: replied 1 month ago.
Tim, you're an early riser, so i missed you today. I can't afford the $45 which the JustAnswer site quoted. I already just paid $37 asking the same questions essentially, had a very good helper who stuck with me many hours! But I had a bad multimeter and my helper didn't know how more to help if I couldn't get 120 volts anyplace. He sent me on to someone else. You are the first to answer.I just can't afford it now though.
Expert:  Tim H. replied 1 month ago.

OK, understand

Customer: replied 1 month ago.
Hello Tim I need help.
Expert:  Tim H. replied 1 month ago.

There will be a charge, however.

Customer: replied 1 month ago.
Do you know how much it will cost? I don't know where to look to find out exactly how much.
Expert:  Tim H. replied 1 month ago.

Question is set for $22.50.

Customer: replied 1 month ago.
I can do that, thanks. My questions are about the transformer, the furnace off/on switch, and the 'neutrals' on the control board. I replaced the control board--no power to furnace. Replaced transformer yesterday but accidently put it in upside down and so the primary-secondary wires were put on backwards. I flipped on breaker. Loud buzzing, red light came on computer board, transformer had white smoke, I cut breaker off. Removed and flipped transformer wires, it smoked again but no power to board this time. I took it off, transformer beeps in ohmeter on secondary side only. Also I took the switch out altogether because it didn't work.
Customer: replied 1 month ago.
my ? about the white wire 'neutrals' for control board--does it matter which spot they occupy out of the 3 spots? Today I'm going to get another transformer,, do I need to put a switch back on it? It was a switch that had an empty spot where a screw- in old S15 fuse, but the switch did used to work as off/on without the fuse. What kind of switch do I buy? There are 3 screws on old switch
Expert:  Tim H. replied 1 month ago.

You will need both a new transformer and a new board. I'm off to work now, but can reply later.

Customer: replied 1 month ago.
Hello Tim,
A.) The transformer I can get locally at Home Depot but the board I had to order from ebay and it took a week or so, is there a way to test the board? maybe it's still good, or even the one I had on there to begin with? [test]--since apparently it needed a transformer all along--MAYBE a new board, I'd like to save time and keep a board I have if still good.
B.) Also the 3 white wires on the board pins called "NEUTRALS"--Do they need to be in a special order?
C.) The transformer says 120VAC PRI, 24VAC SEC, 40 V.A., 50/60HZ, CLASS 2, 130-G.
I have a transformer here that is good and says all the same things, except it is 10 V.A. instead of 40 V.A. Can I temporarily hook it up to see if board works?
D. Do I need to have a toggle switch for the furnace or can the 120 from Main go straight to the board like it does now?
Expert:  Tim H. replied 1 month ago.

Neutrals do not need to be in any order. I doubt a 10VA will effectively replace a 40 VA. It is not powerful enough. You could certainly try it. Worst that can happen is it will burn out because it's not high enough VA rating. There should always be a shut off switch (light switch) for the furnace.

Customer: replied 1 month ago.
Hi Tim,
I re-attached the old switch, and even in OFF position, I had 120v going to the control board, --normal?
And when I flipped the switch ON, it kicked the breaker in Main Breaker Box.
I didn't try the 10VA transformer, I did this with no transformer attached at all, wires for a transformer are just attached on the one end they originate from. Does this kicked breaker happen with switch ON because the circuit needs an attached transformer?
Customer: replied 1 month ago.
I disconnected the outlet below the switch and it's not connected to anything.
Expert:  Tim H. replied 1 month ago.

Could be a bad switch shorted to ground. Or a dead short somewhere else in the high voltage side (120 volt). Yes boards should have voltage to L1 which is a hot. But this will come through the shut off switch first.

Customer: replied 1 month ago.
Thanks Tim,
When I connected the switch [shown here], I put the Green Ground wire onto the back of the recessed fuse holder screw, Black wire on gold colored screw, White Neutral on silver. Is that right? I tried the ohms "beep" test-- leads on left and right screws--and when switch is ON, It beeps, switch OFF, nothing. In regular ohms, both ON and OFF on switch there are no numbers registering.
Expert:  Tim H. replied 1 month ago.

Yes, gold is hot, silver is neutral.

Customer: replied 1 month ago.
Does the switch sound bad? [beeps, ohms]? And the fact that it lets 120v through it in the OFF position?
Expert:  Tim H. replied 1 month ago.

Yes, it shouldnt do that. Replace the switch.

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